The eminent evolutionary biologist E.O. Wilson has an audacious vision for saving Earth from a cataclysmic extinction event

The bison weren’t thundering as we moved slowly through them, merely standing around massively, impressively, the calves frisky, the bulls larger than our truck. It seemed to take forever to get past the great herd. Then we struck off cross-country and uphill. “Let’s go howl at the wolves,” Phillips said. A bald eagle perched on a fencepost, a couple of four-foot-tall, reddish sandhill cranes stalked sedately through rolling, grassy slopes filled with purple lupine, white yarrow and yellow blanket flowers. We stopped at a high, sweet-smelling meadow and, once Phillips cut the engine, an enormous silence enveloped us, broken only by the buzzy trill of a song sparrow.

We had to whisper because sounds carried so well in this natural amphitheater. Valpa Asher, the TESF wolf biologist accompanying us, told us some wolves might show up, about a mile away. “You’ll think they’re floating,” she said quietly. “Wolves are all leg.” They’d be at eye level halfway up a steep, rocky slope over on the far side of a deep valley. No guarantees, of course. We were looking at a “rendezvous site,” a kind of aboveground den, where wolf pups that were old enough get brought to learn the landscape.

Farther away, the skyline was dominated by the pointed crests of the Spanish Peaks, snowcapped even in summer. There was a rumble of thunder, and it suddenly started to pour. Wind whistled in our ears. It got colder, and we retreated to the truck, where Phillips broke out deli sandwiches and cans of Jamaican lemonade. Then the sun came out again, and there was a double rainbow to our right. “The D is showing off—this is too cool,” Phillips said matter-of-factly, far more restrained than YouTube’s “double rainbow guy.”

Then—there they were. Dots to the naked eye, but vividly close through a spotting scope. A black adult, a gray adult with a black ruff and six pups, four black and two gray, gamboling, sniffing the ground, chasing each other, dispersing and then regrouping.

Definitely floating. Phillips grinned, threw his head back and howled across the valley. On the other side, the two adult wolves threw back their heads and howled. The sounds were faint but unmistakable. For the moment, at least, Half Earth felt whole.